1. Field of the Invention
The invention relates to a telecommunication network, more specifically a telephony network, comprising a plurality of nodes which are coupled to each other by means of transmission lines. Each node comprises a switching module, a central module and at least one peripheral module to which user ports can be connected. A control unit for operational maintenance is coupled to one of the nodes which unit can supply a command consisting of a sequence of sub-commands for modifying the data in one or more nodes in the network.
2. Prior Art
Such a telecommunication network is generally known and is used in, for example, company telephone exchanges. The network is then assembled from self-contained nodes each managing the variable and (semi)-permanent data of its "own" terminals connected to that node.
If now one wants to make changes, by means of operational maintenance, in the data file of one or more nodes, for example because a telephone connection associated with one node is to be "moved" to a different node, whilst maintaining its own set number and all further facilities associated with that set number, such as the possibility of trunk and international calls, it is imperative that a protection is provided which insures that during the "move", that is to say during the change in the data in the relevant nodes, no information is lost because of the fact that, for example, an interruption occurs in the transmission line between the node from which operational maintenance is to be effected and a node in which data must be changed. Such an interruption may be caused by "hardware" faults, such as faults in the equipment or a physical interruption of the transmission line.